Trade would expand throughout the century and by the 1690s it was making mega-fortunes for those involved in Leeds (on the Aire) and Wakefield (on the Calder) - money to be invested in improved transport, which in those times meant waterways.
The tide flowed up the Aire to Knottingley, so navigation that far upstream was possible for small craft on suitable tides, and free of charges which was good, but it was a long way from the two booming towns deep in the Yorkshire hills.
Fish, eel, lamprey, otter up-pass.
But the A&C hadn’t finished - Selby was limited by only having a small basin above the lock, and no room to excavate more so in 1820 they started on their major works, to build a very wide canal all the way from Knottingley to Goole, a small village further downstream from Selby. That way they could also avoid further bends on the Ouse, have direct access to deeper water on the river, and have room to create docks for ships and canal traffic. This was not a company to do things half-heartedly! By 1826 they had completed the task, with the only lower part of the Aire now used by boats the short stretch between Knottingley and Haddesley, to give access to the Selby Canal.
Of course, by then, the wool trade of Leeds & Wakefield had abated - coal was the next source of riches for the Aire & Calder Navigation.